26 t THE OCEAN. 



Form'd harbours, safe at once aud perilous — 

 Safe for defence, but perilous to enter. 

 A sea-lake shone amidst the fossil i.sle. 

 Reflecting in a ring its cliSs and caverns, 

 With heaven itself seen like a lake below." * 



The islands of the second class seem to have been 

 originally of the same structure as those already 

 noticed, but have been elevated to the height of 

 one hundred to five hundred feet, by some unknown 

 agency. The character of their vegetation resem- 

 bles that of the volcanic isles, of which I shall pre- 

 sently speak, but they do not possess their sub- 



cbyhtal island. 



lime grandeur, nor the peculiar loveliness of the 

 atolls. The rocks are crystallized carbonate of lime, 

 supposed to have been originally coral, "but, by 



* Montgomery's Pelican Island. 



